Analysis of single-cell sequencing data also showed that IL-35 was mainly expressed at higher levels in the CD4+ T cell population in the tumor microenvironment (Fig. 3C), and analysis by expression and cell composition correlation suggested that CD4-CXCL13-Tfh, CD4-CCR7-FOS cells may increase the immunosuppressive CD4-CTLA4-Treg occupancy by expressing IL-35, resulting in an immunosuppressive immune microenvironment (Fig. 3D). The gene discussed is FOS; the disease is neoplasm.